iPhone OS 3.0上的录音错误kAudioQueueErr_CannotStart

I'm working on a couple different iphone apps that both record and play sounds concurrently. Think multitrack mixing... play one sound a save it then listen to that sound while recording the next sound to another file. My mechanism for this has been to start up two different audio queues, one for recording, and one for playing.I'm working on a couple different iphone apps t